Description of the Related Art
There has been known a flash memory that accumulates electric charges on an electric charge accumulating layer and a floating gate to store data. Such flash memory is connected by various methods such as a NAND type and a NOR type, thus constituting a semiconductor memory device. Recently, such semiconductor memory devices have been large capacity and highly integrated. Then, to ensure a large capacity and a high integration, a semiconductor memory device whose memory cells are three-dimensionally disposed (three-dimensional semiconductor memory device) has been proposed. Ensuring both to have a large capacity and to be downsized has been also desired.